Improvement in hoisting apparatus



2 Sheets-Sheet 1.

v 0. E. .ALBRO. Hoisting Apparatus.

Patented March 5, 1878.

S E S S E N l 1 W ATTORNEYz? 2 Sheeta-Sheet 2.

0. E. ALBRO. .DJQ'TL'IF'Z..,$H0isting Apparatus.

No. 200,961. Patented March 5, 1878.

N. PETERS. PNOTDJJTNOGRAFHER. WASHINGTON D C l l l l.

UNITED Srnrns PATENT OFFICE.

CHARLES E. ALBRO, on CORTLAND, rnw YORK.

IMPROVEMENT lN HOISTING APPARATUS.

' Specification forming part of Letters Patent No. 200,961, dated March5, 1878; application filed December 22, 1877.

To all whom it may concern:

Be it known that I, CHARLES E. Ammo, of the village of Cortland, countyof Cortland and State of New York, have invented new and usefulImprovements in Self-Sustaining Differential Hoisting Apparatus, whichimprovements are fully set forth in the following specification andaccompanying drawings, reference being had to the said drawings, and tothe letters and figures of reference marked thereon. T

' The object of my invention is to provide a .self-sustainin gdifferential hoisting apparatus, the mechanism of the same being placedin a suitable frame-work or shell, so that it can be used like anordinary pulley-blo ck to raise and lower heavy weights, as required inmachineshops, and for the various other purposes for which the ordinarypulley-block, and tackle and differential pulleys are now used.

My invention relates to that class of hoisting apparatus-inwhich themechanism, of the same is placed in a suitable frame-work, and can behung up or suspended like an ordinary pulley-block; and my inventionconsists in a suitable frame, in which is journaled a shaft broken away,showing the endless screw. Fig.

3 represents a front view of the wheel part of the endless screw and thedifferential pulleys, with a portion of the supporting-frame. Fig. drepresents a view showing the wheel part of two endless screws, theconnecting spur-wheels, and a different arrangement of the differentialpulleys with the supporting-frame. Fig. 5 represents a horizontalsectional view on the line a; 00 of Fig. 4.

In the drawings the same letters on the different figures indicate thesame parts.

In the drawings, A A A A, A and A is the frame-work, which is made inthe form shown in the different figures, and of metals of sufficientsize and strength to stand the strains to which it will be subjected. Band B are swivelhooks on this frame. Their use is evident. D is thewheel part of the endless screw. Fa-stened rigidly to the wheel part Dare the two chain-pulleys H and H, all of which revolve on the shaft oraxle I I. The chain-pulley H is of a larger diameter than thechain-pulley H.

In chain-wheel H, b I) b, and in chainwheel H a a a, are sprockets, tokeep the chain from slipping or sliding. P is the drive-pulley, the axleO of which has the screw part of the endless screw, as shown in Fig. 2,the said axle 0 having hearings in the parts A and A of thesaidframe-work, which parts are fastened to the other part by the screwsn n.

In Fig. 2, t and s are teeth on the wheel, and r and 61 threads ofscrew, showing how they engage each other.

The drive-pulley P is fastened to the axle O by the hub E and screw J.This drive-pulley P has sprockets w, y, and z in its concave rim, forthe purpose of preventing the endless rope or chain used thereon fromslipping or sliding.

In Fig. 3, M is the sheave of the snatchblock; 1), the axle of the same.T, T, and T are guards. S is a hook in the same.

In the construction of all of the parts of my apparatus I make use ofmaterials of such a size and strength as will stand all the strains towhich the apparatus will be subjected in the use for which it isintended.

Having thus described the construction of my apparatus, I Will nowproceed to describe its use and operation.

The frame-work is suitably suspended by the swivel-hook B. Over thechain-pulleys H and H is placed the chain, as shown in Fig. 3. R and Ris the chain. This chain then passes under the sheave M, and the weightto be raised is connected with the hook S. It will be noticed that thechain R passes over the larger chain-pulley H on a different side thanthe chain B does on the smaller chain-pulley H, so that the chain Itunwiuds while the chain R winds up, and vice yersa. The chain It and Rcan be made endless.

It will thus be seen that a differential IIlO- tion is produced, andthat comparatively little power is required to turn the pulley P, as thethrust on the screw on the axle G is only slight.

It will readily be further seen that the screw on the axle C, whenturned by the pulley P, imparts motion to the wheel part D; but thewheel part D cannot in any way impart motion to the screw on the axle C,from which it is plain that the apparatus is self-sustaining, and theweight must remain suspended at any point desired, and cannot run down.

It will be seen that when the chain is put on the chain-pulleys H and H,as shown in Fig. 3, the weight is raised very slowly; but when greaterspeed is required, with a corresponding loss of power, I put the chainsR and R on the chain-pulleys H and H, both on the same side, so thatthey both wind up, as shown by the arrows in Fig. 1; but when put on inthis way power is exchanged for space and time. The chain It can be put,if desired, on only one of the chain-pulleys, as H, the other end beingput on the hook B; or the said other end may be hitched direct to theweight to be raised.

It will be readily seen that the important feature of my invention isthe endless screw with the chain-pulleys fastened rigidly to the wheelpart of the said endless screw, and that the said chain-pulleys H and Hcan be made to vary greater in diameter than the sheaves in the ordinarydifferential pulley, for the reason that the screw part of the saidendless screw makes my apparatus absolutely self-sustaining, and itcannot run down; and, in addition, I get all the advantages of the powerproduced by the said endless screw.

It willbe further seen that where great power is not required I candispense with one of the said chain-pulleys and let the chain pass overthe other one, and thus form a self-sustaining hoisting apparatus, whichwill be found cheap and convenient in many places where great power isnot required. Where very great power is required, and there may bedanger of tearing the teeth ofl the wheel part D or the thread of thescrew part on the axle C, I make use of two endless screws, connectedtogether by suitable spur-gearing, the wheel parts of the said endlessscrews being where the chainpulleys H and H now are, and next to A andA, and the said chain-pulleys being side by side between the said wheelparts of the said endless screws.

In the form and construction of the framework A, A, A A, A and A theform shown need not be exactly followed; but the framework must be madestrongly and substantially, with proportions adapted to the use forwhich it is intended.

I am aware that differential-pulleys operated by an endless screw haveheretofore been employed in hoisting apparatus, and this I do not claimbroadly; but

What I claim is 1. In combination with the wheel part of the endlessscrew, the differential pulleys mounted at each side thereof, and thesupporting-frame of the screw part journaled in detachable bearings A,the whole constructed and arranged substantially as specified.

2. In a hoisting apparatus, the combination, with the differentialpulleys of the wheel'part, of two endless screws located one on eachside of the pulleys and on the same shaft, and two screw parts gearinginto said wheel parts and j ournaled in detachable bearin gs,substantially as and for the purpose specified.

3. In a hoisting apparatus, the frame-work A, A A, A", A", and A,swivel-hooks B and B, substantially as described, in combination withone or more endless screws, the difi'erential pulleys H and H,drive-wheel P, and axle or shaft I I, all substantially in the mannerand for the purpose herein shown and specified.

CHAS. E. ALBRO.

Witnesses:

FRANKLIN PIERCE, H. J. HARRINGTON.

